High-temperature shell-and-tube heat exchanger
Technical Field
The invention belongs to the technical field of heat exchanger equipment, and particularly relates to a high-temperature shell-and-tube heat exchanger.
Background
The shell-and-tube heat exchanger is a dividing wall type heat exchanger which uses the wall surface of the tube bundle enclosed in the shell as the heat transfer surface, and the heat exchanger has simple structure, low cost, wide flow cross section and easy scale cleaning, but has low heat transfer coefficient and large floor area, can be made of various structural materials (mainly metal materials), can be used under high temperature and high pressure, and is the most widely applied type.
According to CN109654909B superfine shell-and-tube heat exchanger of high temperature high pressure, among the prior art, when heating low temperature water through hot steam, surface condensation liquefaction at the water pipe through the inside steam of hot steam, realize that the inside heat conduction of hot steam goes into low temperature water, carry out quick heating to low temperature water, but a large amount of hot steam is converged at the surface condensation of water pipe, can serious influence next heat exchange efficiency, and low temperature water is at the in-process that is heated, the internal surface of water pipe is adhered to the mineral substance that contains easily of low temperature water, the heat exchange tube is used for a long time afterwards, the internal surface of water pipe can a large amount of mineral substances of adhesion, and then also can seriously influence heat exchange efficiency scheduling problem.
In view of this, in order to overcome the above technical problems, the present company has designed and developed a high temperature shell-and-tube heat exchanger, which solves the above technical problems.
Disclosure of Invention
In order to make up the defects of the prior art and solve the problems that in the prior art, when low-temperature water is heated by hot steam, water vapor in the hot steam is condensed and liquefied on the surface of a water pipe, the heat in the hot steam is conducted into the low-temperature water, the low-temperature water is rapidly heated, but a large amount of hot steam is condensed and collected on the outer surface of the water pipe and can seriously influence the subsequent heat exchange efficiency, in the process of heating the low-temperature water, mineral substances contained in the low-temperature water are easily adhered to the inner surface of the water pipe, and after the heat exchange pipe is used for a long time, the inner surface of the water pipe can be adhered with a large amount of mineral substances, so that the heat exchange efficiency is seriously influenced, and the.
The technical scheme adopted by the invention for solving the technical problems is as follows: the invention relates to a high-temperature shell-and-tube heat exchanger, which comprises a shell, a water pipe and a hot air pipe; the pipe shell is designed into a cylindrical structure; a cavity is formed in the tube shell; the left side surface and the right side surface of the pipe shell are provided with mounting holes at the axial line positions of the pipe shell; the insides of the two mounting holes are fixedly connected with the same water pipe; a hot air pipe is fixedly connected between the left inner surface and the right inner surface of the pipe shell at the position of the water pipe, the hot air pipe is sleeved outside the water pipe, the cross section of the hot air pipe is designed into a triangular structure, and the vertex position of the triangle is rounded; the upper surface of the pipe shell is fixedly connected with a power box body; a power groove is formed in the power box body; the upper surfaces of the pipe shell and the hot air pipe are fixedly connected with the same air inlet pipe at the position close to the left side surface of the pipe shell; the upper surfaces of the pipe shell and the hot air pipe are fixedly connected with the same air outlet pipe at the position close to the right side surface of the pipe shell; the power block is fixedly connected inside the power box body; an air cavity is formed in the power block, and an air column is rotatably connected in the air cavity; the outer surface of the wind column is fixedly connected with uniformly arranged fan blades at the position of the wind cavity; the upper surface of the power block is fixedly connected with a reversing valve, the reversing valve is respectively communicated with the air inlet pipe and the air cavity, and the air outlet of the air cavity is communicated with the air outlet pipe; the outer surface of the wind post is fixedly connected with a first gear at a position close to the right side face of the wind post; a second gear is meshed and connected with the lower position of the first gear; the lower surface of the second gear is fixedly connected with a power column; the lower end surface of the power column penetrates through the pipe shell and the pipe wall of the hot air pipe and extends into the hot air pipe; a sealing rotating ring is arranged between the power column and the hot air pipe; the outer arc surface of the power column is fixedly connected with a transmission gear at a position close to the lower surface of the power column; toothed plates are meshed and connected in the left and right directions of the transmission teeth; the outer surface of the hot air pipe is provided with clean water rings at the left side and the right side of the power column; when the high-temperature shell-and-tube heat exchanger is used for heating low-temperature water, two modes are commonly used, wherein the first mode is that the low-temperature water is subjected to heat exchange heating through hot steam, and the second mode is that the low-temperature water is subjected to heat exchange heating through high-temperature water, in the prior art, when the low-temperature water is heated through the hot steam, the heat inside the hot steam is transferred into the low-temperature water through the condensation and liquefaction of water vapor on the surface of a water pipe, the low-temperature water is rapidly heated, but a large amount of hot steam is condensed and collected on the outer surface of the water pipe, the subsequent heat exchange efficiency can be seriously influenced, in addition, in the heating process of the low-temperature water, mineral substances contained in the low-temperature water are easily adhered to the inner surface of the water pipe, after a heat exchange pipe is used for a long time, a large amount of mineral substances can be adhered to the inner, when low-temperature water needs to be heated, low-temperature water is firstly led into the heat exchanger through the left end face of the water pipe, high-pressure hot steam is led into the hot air pipe continuously through the air inlet pipe, low-temperature water is heated, simultaneously high-pressure hot steam is led into the air cavity synchronously, the air column is driven to rotate by driving the fan blades, the air column drives the first gear to rotate, the first gear drives the second gear to rotate in a gear meshing mode, the second gear further drives the power column to rotate, the power column can drive the toothed plate to move left and right through the transmission teeth on the surface of the power column, the toothed plate further drives the clear water ring to move left and right, and condensed water on the outer surface of the water pipe is removed. Avoid a large amount of the collection of comdenstion water at the surface of water pipe, form the one deck water layer, influence subsequent heat exchange efficiency, and can clear away a large amount of mineral substances of water pipe internal surface adhesion in step, avoid the influence of the soda that the mineral substance formed to heat exchange efficiency.
Preferably, the two clear water rings are provided with evenly distributed rotating holes relative to the side surface of one side of the hot air pipe; rolling balls are rotatably connected inside the rotating holes; rotating shafts are rotatably connected between the rolling balls and the corresponding rotating holes and are not perpendicular to the axis of the clear water ring; the right side surfaces of the clear water rings are provided with rotary grooves, and the toothed plates are rotatably connected in the corresponding rotary grooves; wiping plates are arranged at the side surfaces of the two clear water rings, which are far away from the toothed plates; the during operation sets up the spin of evenly arranging through the internal surface at clear water ring, rotates round the pivot that corresponds the slope through the spin for clear water ring can do synchronous rotation round the surface of water pipe when being guided about by the pinion rack, and the spin also can reduce the frictional force between clear water ring and the water pipe surface by a wide margin, can effectually get rid of the comdenstion water on water pipe surface through the board of wiping on clear water ring surface.
Preferably, the outer cambered surfaces of the two clear water rings are rotatably connected with lantern rings; adjusting plates are arranged between the lantern rings and the corresponding clear water rings; uniformly arranged springs are fixedly connected between the adjusting plates and the corresponding lantern rings; the side surface of the adjusting plate, which is far away from the toothed plate, is fixedly connected with convex balls which are uniformly and non-uniformly arranged; the side surface of one side of the adjusting plate relative to the toothed plate is fixedly connected with the wiping plate; the during operation, through setting up the regulating plate, when wiping the board and carrying out the clear water operation on the surface to the water pipe, the frictional force between wiping board and the water pipe is great, and then the wiping board can produce tangential effort to the regulating plate, produce relative rotation between regulating plate and the clear water ring, the protruding ball that the regulating plate surface evenly arranged and the spring action between cooperation regulating plate and the lantern ring, can realize moving about of regulating plate, and then the regular automatic extrusion to the wiping board, make the saturation phenomenon can not appear in the inside moisture of wiping board, improve the ability of absorbing water of wiping the board.
Preferably, cleaning rings are fixedly connected to the positions of the two clear water rings in the water pipe; the cleaning ring is designed by magnetic materials; the side surface of one side of the cleaning ring relative to the water pipe is connected with balls which are uniformly distributed in a rolling way; the during operation sets up the clearance ring through the inside at the water pipe, through being magnetic material with the design of clearance ring for the clearance ring can drive in step the clear water ring, realizes that the clearance ring constantly clears away the operation of soda, can play the effect of reducing friction through the ball that sets up evenly arranging on the surface of clearance ring.
Preferably, the side surfaces of the left side and the right side of each of the two cleaning rings are fixedly connected with scrapers which are uniformly arranged; the upper part, the left part and the right part of the scraper are both in scraping edge structural design; during operation, through the scraper that sets up evenly arranged in the left and right sides side at clearance ring, can promote the ability that clearance ring clears away water pipe internal surface water and alkali by a wide margin through the effect of scraper.
Preferably, the surface of the cleaning ring is provided with uniformly arranged adjusting holes; the inner parts of the adjusting holes are fixedly connected with adjusting blocks; the side surface of one side of each adjusting hole is fixedly connected with a first telescopic rod; the adjusting blocks are provided with adjusting grooves relative to the side surface of one side of the axis of the cleaning ring; the inner parts of the adjusting grooves are all connected with sliding blocks in a sliding manner; the sliding blocks are fixedly connected with second telescopic rods at the side surface of one side of the bottom of the corresponding adjusting groove; the side surfaces of the sliding blocks, which are far away from the inner surfaces of the cleaning rings, are fixedly connected with the same elastic membrane, and the elastic membrane is fixedly connected with the inner surfaces of the corresponding cleaning rings; the during operation, through setting up the regulating block, when the clearance ring moves along the rivers direction, the adjustable ring can extrude first telescopic link, make the inside gas of first telescopic link enter into the inside of the second telescopic link that corresponds, the second telescopic link is ejecting, the second telescopic link and then can drive the slider that corresponds ejecting, the slider all can jack-up elastic membrane, realize the change of clearance ring internal diameter, the internal diameter of clearance ring reduces, the low temperature water that flows can drive the clearance ring automatically and remove, play the effect that promotes the shift ring motion and clear away the water alkali.
The invention has the following beneficial effects:
1. according to the high-temperature shell-and-tube heat exchanger, the shell tube, the water pipe and the hot air pipe are arranged, the clear water pipe is arranged on the outer surface of the water pipe, and the cleaning ring is arranged on the inner surface of the water pipe, so that the condensed water collected by continuously condensing the outer surface of the water pipe is effectively removed in real time, a large amount of condensed water is prevented from being collected on the outer surface of the water pipe to form a water layer, the subsequent heat exchange efficiency is influenced, a large amount of mineral substances adhered to the inner surface of the water pipe can be synchronously removed, and the influence of water alkali formed by the mineral.
2. According to the high-temperature shell-and-tube heat exchanger, the adjusting block, the sliding block and the elastic membrane are arranged, when the cleaning ring moves along the water flow direction, the adjusting ring can extrude the first telescopic rod, so that gas in the first telescopic rod enters the corresponding second telescopic rod, the second telescopic rod is ejected, the second telescopic rod can further drive the corresponding sliding block to eject, the sliding blocks can jack up the elastic membrane, the change of the inner diameter of the cleaning ring is realized, the inner diameter of the cleaning ring is reduced, flowing low-temperature water can automatically drive the cleaning ring to move, and the effects of promoting the movement of the moving ring and removing water and alkali are achieved.
Drawings
The invention will be further explained with reference to the drawings.
FIG. 1 is a perspective view of the present invention;
FIG. 2 is a top view of the present invention;
FIG. 3 is a cross-sectional view taken at A-A in FIG. 2;
FIG. 4 is a perspective view of a component of the cleaning ring of the present invention;
FIG. 5 is a cross-sectional view of a component of the cleaning ring of the present invention;
FIG. 6 is an enlarged partial view at B in FIG. 3;
FIG. 7 is an enlarged partial view at C of FIG. 3;
in the figure: the device comprises a pipe shell 1, a power box body 11, an air inlet pipe 12, an air outlet pipe 13, fan blades 14, a first gear 15, a second gear 16, a power column 17, a water pipe 2, a cleaning ring 21, an adjusting block 22, a first telescopic rod 23, a sliding block 24, a second telescopic rod 25, an elastic membrane 26, a hot air pipe 3, a toothed plate 31, a clear water ring 32, a rolling ball 33, a wiping plate 34, a lantern ring 35, an adjusting plate 36, a spring 37 and a convex ball 38.
Detailed Description
In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further described with the specific embodiments.
As shown in fig. 1 to 7, the high-temperature shell-and-tube heat exchanger of the present invention comprises a shell-and-tube 1, a water tube 2 and a hot gas tube 3; the pipe shell 1 is designed into a cylindrical structure; a cavity is formed in the tube shell 1; the left side surface and the right side surface of the pipe shell 1 are provided with mounting holes at the axial line position of the pipe shell 1; the same water pipe 2 is fixedly connected to the inner parts of the two mounting holes; a hot air pipe 3 is fixedly connected between the left inner surface and the right inner surface of the pipe shell 1 at the position of the water pipe 2, the hot air pipe 3 is sleeved outside the water pipe 2, the cross section of the hot air pipe 3 is designed into a triangular structure, and the vertex position of the triangle is rounded; the upper surface of the pipe shell 1 is fixedly connected with a power box body 11; a power groove is formed in the power box body 11; the upper surfaces of the pipe shell 1 and the hot air pipe 3 are fixedly connected with the same air inlet pipe 12 at the position close to the left side surface of the pipe shell 1; the upper surfaces of the pipe shell 1 and the hot air pipe 3 are fixedly connected with the same air outlet pipe 13 at the position close to the right side surface of the pipe shell 1; a power block is fixedly connected inside the power box body 11; an air cavity is formed in the power block, and an air column is rotatably connected in the air cavity; the outer surface of the wind column is fixedly connected with uniformly arranged fan blades 14 at the position of the wind cavity; the upper surface of the power block is fixedly connected with a reversing valve, the reversing valve is respectively communicated with the air inlet pipe 12 and the air cavity, and an air outlet of the air cavity is communicated with the air outlet pipe 13; the outer surface of the wind post is fixedly connected with a first gear 15 at the position close to the right side face of the wind post; a second gear 16 is meshed and connected with the lower position of the first gear 15; the lower surface of the second gear 16 is fixedly connected with a power column 17; the lower end surface of the power column 17 penetrates through the pipe walls of the pipe shell 1 and the hot air pipe 3 and extends into the hot air pipe 3; a sealing swivel is arranged between the power column 17 and the hot gas pipe 3; the outer arc surface of the power column 17 is fixedly connected with a transmission gear at a position close to the lower surface of the power column 17; a toothed plate 31 is meshed and connected to the left and right directions of the transmission gear; the outer surface of the hot air pipe 3 is provided with clear water rings 32 at the left and right sides of the power column 17; when the heat exchange tube works, when low-temperature water is heated through the high-temperature tube shell 1 type heat exchanger, two modes are commonly used, wherein the first mode is that the low-temperature water is heated through heat exchange through hot steam, the second mode is that the low-temperature water is heated through heat exchange through high-temperature water, in the prior art, when the low-temperature water is heated through the hot steam, the water vapor in the hot steam is condensed and liquefied on the surface of the water tube 2, the heat in the hot steam is conducted into the low-temperature water, the low-temperature water is rapidly heated, but a large amount of hot steam is condensed and collected on the outer surface of the water tube 2, the next heat exchange efficiency can be seriously influenced, in the heating process of the low-temperature water, mineral substances contained in the low-temperature water are easily adhered to the inner surface of the water tube 2, after the heat exchange tube is used for a long time, a, when low-temperature water needs to be heated, low-temperature water is firstly led into the heat exchanger through the left end face of the water pipe 2, high-pressure hot steam is continuously led into the hot air pipe 3 through the air inlet pipe 12, heating of the low-temperature water is achieved, meanwhile, the high-pressure hot steam is synchronously led into the air cavity, the air column is driven to rotate by driving the fan blades 14, the air column drives the first gear 15 to rotate, the first gear 15 drives the second gear 16 to rotate in a gear meshing mode, the second gear 16 further drives the power column 17 to rotate, the power column 17 can drive the toothed plate 31 to move left and right through the transmission teeth on the surface of the power column, the toothed plate 31 further drives the clear water ring 32 to move left and right, and removal of condensed water on the outer surface of the water pipe 2 is achieved, through the high-temperature shell-and-tube heat exchanger, the effectual condensed water that has realized gathering the continuous condensation of water pipe 2 surface carries out real-time cleaing away, avoids the condensed water to gather in a large number at the surface of water pipe 2, forms the one deck water layer, influences subsequent heat exchange efficiency, and can clear away the 2 internal surface adhesion's of water pipe a large amount of mineral substances in step, avoids the influence of the soda that the mineral substance formed to heat exchange efficiency.
As an embodiment of the present invention, the two clean water rings 32 are provided with evenly arranged rotating holes at the side positions of one side relative to the hot air pipe 3; the rolling balls 33 are rotatably connected inside the rotating holes; rotating shafts are rotatably connected between the rolling balls 33 and the corresponding rotating holes and are not perpendicular to the axis of the clear water ring 32; the right side surfaces of the clear water rings 32 are respectively provided with a rotary groove, and the toothed plates 31 are respectively rotatably connected in the corresponding rotary grooves; the side surfaces of the two clear water rings 32, which are far away from the toothed plate 31, are provided with wiping plates 34; the during operation, through the spin 33 that sets up the even arrangement at the internal surface of clear water ring 32, rotate round the pivot that corresponds the slope through spin 33 for clear water ring 32 can do synchronous rotation round the surface of water pipe 2 when being guided about by pinion rack 31, and spin 33 also can reduce the frictional force between clear water ring 32 and the 2 surfaces of water pipe by a wide margin, and the comdenstion water on 2 surfaces of water pipe can effectually be got rid of through clear water ring 32 surperficial wipe board 34.
As an embodiment of the present invention, the outer arc surfaces of the two clear water rings 32 are both rotatably connected with a collar 35; an adjusting plate 36 is arranged between the lantern ring 35 and the corresponding clear water ring 32; uniformly arranged springs 37 are fixedly connected between the adjusting plates 36 and the corresponding lantern rings 35; the side surface of the adjusting plate 36, which is far away from the toothed plate 31, is fixedly connected with convex balls 38 which are uniformly and non-uniformly arranged; the side surface of the adjusting plate 36 opposite to one side of the toothed plate 31 is fixedly connected with the wiping plate 34; the during operation, through setting up regulating plate 36, when wiping board 34 when carrying out the clear water operation to the surface of water pipe 2, it is great to wipe the frictional force between board 34 and the water pipe 2, and then wiping board 34 can produce tangential effort to regulating plate 36, produce relative rotation between regulating plate 36 and the clear water ring 32, the protruding ball 38 and the cooperation regulating plate 36 that the regulating plate 36 surface was evenly arranged and the spring 37 effect between the lantern ring 35, can realize about removing of regulating plate 36, and then the regular automatic extrusion to wiping board 34, make the saturation phenomenon can not appear in the inside moisture of wiping board 34, improve the ability of absorbing water of wiping board 34.
As an embodiment of the present invention, the cleaning rings 21 are fixedly connected to the two clean water rings 32 inside the water pipe 2; the cleaning ring 21 is designed by magnetic materials; the side surface of one side of the cleaning ring 21 relative to the water pipe 2 is connected with balls which are uniformly distributed in a rolling way; the during operation sets up clearance ring 21 through the inside at water pipe 2, through designing clearance ring 21 for magnetic material for clearance ring 21 can drive clear water ring 32 in step, realizes that clearance ring 21 constantly clears away the operation of soda, can play the effect of reducing friction through the ball that sets up evenly arranging on the surface at clearance ring 21.
As an embodiment of the invention, the side surfaces of the left and right sides of the two cleaning rings 21 are fixedly connected with scrapers which are uniformly arranged; the upper part, the left part and the right part of the scraper are both in scraping edge structural design; during operation, through set up the scraper of evenly arranging in the left and right sides side of clearance ring 21, can promote the ability that clearance ring 21 clears away the inside surface water alkali of water pipe 2 by a wide margin through the effect of scraper.
As an embodiment of the present invention, the surface of the cleaning ring 21 is provided with uniformly arranged adjusting holes; the interior of each adjusting hole is fixedly connected with an adjusting block 22; the side surface of one side of each adjusting hole is fixedly connected with a first telescopic rod 23; the adjusting blocks 22 are provided with adjusting grooves corresponding to the side positions of one side of the axis of the cleaning ring 21; the inner parts of the adjusting grooves are all connected with sliding blocks 24 in a sliding manner; the slide blocks 24 are fixedly connected with second telescopic rods 25 at the side surfaces of the corresponding groove bottoms of the adjusting grooves; the side surfaces of all the sliding blocks 24, which are far away from the inner surface of the cleaning ring 21, are fixedly connected with the same elastic membrane 26, and the elastic membranes 26 are fixedly connected with the inner surfaces of the corresponding cleaning rings 21; during operation, through setting up regulating block 22, when clearance ring 21 moves along the rivers direction, the adjustable ring can extrude first telescopic link 23, make the inside gas of first telescopic link 23 enter into the inside of corresponding second telescopic link 25, second telescopic link 25 is ejecting, second telescopic link 25 then can drive the slider 24 that corresponds ejecting, slider 24 all can jack-up elastic membrane 26, realize the change of clearance ring 21 internal diameter, the internal diameter of clearance ring 21 reduces, the low temperature water that flows can drive clearance ring 21 automatically and remove, play the effect that promotes the removal ring motion and clear away the water alkali.
The specific working process is as follows:
when the low-temperature water heating device works, when low-temperature water needs to be heated, low-temperature water is firstly led into the heat exchanger through the left end face of the water pipe 2, high-pressure hot steam is led into the hot air pipe 3 continuously through the air inlet pipe 12, heating of the low-temperature water is achieved, meanwhile, the high-pressure hot steam is also led into the air cavity synchronously, the air column is driven to rotate by driving the fan blades 14, the air column drives the first gear 15 to rotate, the first gear 15 drives the second gear 16 to rotate in a gear meshing mode, the second gear 16 further drives the power column 17 to rotate, the power column 17 can drive the toothed plate 31 to move left and right through the transmission teeth on the surface of the power column, the toothed plate 31 further drives the clear water ring 32 to move left and right, and condensed water on the outer surface of the water pipe 2 is removed; the rolling balls 33 which are uniformly arranged are arranged on the inner surface of the clear water ring 32, and the rolling balls 33 rotate around the rotating shafts which are correspondingly inclined, so that the clear water ring 32 can synchronously rotate around the outer surface of the water pipe 2 while being guided left and right by the toothed plate 31, the rolling balls 33 can also greatly reduce the friction force between the clear water ring 32 and the outer surface of the water pipe 2, and the condensed water on the surface of the water pipe 2 can be effectively removed through the wiping plate 34 on the surface of the clear water ring 32; by arranging the adjusting plate 36, when the wiping plate 34 carries out clear water operation on the surface of the water pipe 2, the friction force between the wiping plate 34 and the water pipe 2 is large, further the wiping plate 34 can generate tangential acting force on the adjusting plate 36, the adjusting plate 36 and the clear water ring 32 rotate relatively, the convex balls 38 uniformly arranged on the surface of the adjusting plate 36 and the action of the spring 37 between the adjusting plate 36 and the lantern ring 35 are matched, the adjusting plate 36 can move left and right, further the wiping plate 34 is regularly and automatically extruded, so that the moisture in the wiping plate 34 cannot be saturated, and the water absorption capacity of the wiping plate 34 is improved; the cleaning ring 21 is arranged in the water pipe 2, the cleaning ring 21 is designed to be made of a magnetic material, so that the cleaning ring 21 can synchronously drive the clean water ring 32, the operation of continuously cleaning the water alkali by the cleaning ring 21 is realized, and the function of reducing friction force can be realized by arranging the balls uniformly distributed on the surface of the cleaning ring 21; the scrapers which are uniformly arranged are arranged on the left side surface and the right side surface of the cleaning ring 21, so that the capability of the cleaning ring 21 for removing the water and alkali on the inner surface of the water pipe 2 can be greatly improved under the action of the scrapers; through setting up regulating block 22, when clearance ring 21 moves along the rivers direction, the adjustable ring can extrude first telescopic link 23, make the inside gas of first telescopic link 23 enter into the inside of corresponding second telescopic link 25, second telescopic link 25 is ejecting, second telescopic link 25 then can drive the slider 24 that corresponds ejecting, slider 24 all can jack-up elastic membrane 26, realize the change of clearance ring 21 internal diameter, the internal diameter of clearance ring 21 reduces, mobile low temperature water can drive clearance ring 21 automatically and remove, play the effect that promotes the movement of removal ring and clear away the water alkali.
While there have been shown and described what are at present considered the fundamental principles of the invention, its essential features and advantages, it will be understood by those skilled in the art that the invention is not limited by the embodiments described above, which are merely illustrative of the principles of the invention, but various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents.